Quantum Corporation

Nec Corporation

Other

Alps Electric Co., Ltd.

Alps Electric (usa) Inc.

Ronald R Moon

Michael G Machado

Daniel E Barnard

Gregg J Uhlendorf

William G Moon

Michael R Hatch

Bruce R Peterson

Hoa V Luong

Patrick M Weiher

Robert P Cloutier

Steven G Campbell

Mark E Strysko

Curtis H Bruner

Thomas G Cooper

Tuong T Quan

Thomas A Tacklind

Clifford M Gold

Donald C Westwood

Avraham Perahia

Richard K Oswald

James H Do

Robert J Kobliska

Klaus-Peter Deyring

James A McDonald, Iii

Bryan T Silbermann

Philip L Steiner

Thomas J Huber

A method and apparatus are provided for recovering servo information in a disk drive for positioning a data transducer head relative to concentric data tracks wherein the head reads user data encoded in a predetermined data code and reads servo information within plural servo sectors embedded in each data track defined on a storage surface of a rotating disk. The data tracks are arranged in plural groups of concentric tracks within concentric zones wherein each zone has a user data transfer rate selected in relation to disk radius, the servo information being recorded in at least three patterns within each embedded servo sector: a servo sync pattern, a user data code violating pattern, and a servo data bit pattern. A servo data recovery circuit implements the method comprising the steps of:

Servo data recovery circuit for disk drive having digital embedded

A disk file subsystem is disclosed which utilizes a track address decoding circuit which converts the track address which is recorded on the magnetic media in Gray code according to a 1/6 (2,8) run-length-limited recording code to its corresponding binary track address.

Track address detecting means by HDD sector servo method

A servo system for use in a magnetic recording media is disclosed, with the system utilizing short and long address tracks in a predetermined pattern to increase the usable data storage space on the media. A special pattern is utilized following the A and B BURST patterns for each track on the disk to assist in calibration of the drive. In addition, a special pattern is provided preceding the track address portion of the sectors to identify the associated track address as being a long address, a short address or as the origin sector.

Servo system for providing increased recording density and improved

When a rotary-actuator voice coil type disk drive is powered down the actuator arm is moved to a parking position against an I.D. stop by a disk spindle motor back EMF, resulting from the spinning down of the spindle motor. Current is applied by the back EMF through a delay circuit to a latch arm voice coil on one end of a latch arm and forming part of a magnetic circuit including a drive permanent magnet on a ferrous base plate and a ferrous upper plate. Resultant movement of the latch arm overcomes a spring bias of a torsion spring extending between the base plate and pivoted latch arm normally keeping the latch arm in an unlatched position. A latch permanent magnet extends from the other end of the latch arm and is brought into spaced proximity, but not contact, with a ferrous member extending from the actuator arm so that the magnetic force therebetween holds the actuator arm against the I.D. stop in latched position to withstand high shock loadings. Powering the rotary actuator voice coil motor up overcomes the magnetic force and allows the biased torsion spring to move the latch arm to the unlatched position without resultant loss of data storage area.

Active magnetic latch for disk drive and method

A hard disk drive for a computer system including a head disk assembly with a disk platter of approximately one-and-eight-tenths-inch in diameter capable of storing more than forty megabytes. In an embodiment, data tracks on each data surface of the platter are spaced at approximately 2,558 tracks per inch and each data track has approximately 36,000 flux changes per inch. An actuator positions a pair of read/write heads on each platter surface using a voice coil motor to position the heads over a cylinder. A magnetic actuator latch attaches to another magnet on the actuator and locks the heads in a parked position at the innermost diameter of the platter. A spindle motor rotates the platter at approximately 5,400 revolutions per minute. A base plate, with a gasketed surface and a raised lip, hermetically seals with a cover to the base plate such that the platter, the actuator, the actuator latch, and the spindle motor are all contained within. The cover carries a breather filter and recirculating air filter. The raised lip on the base plate prevents direct electrical interference from passing between the base plate and the cover.

Micro miniature hard disk drive

A miniature disk drive achieves storage densities of at least approximately 1700 tracks per inch per storage surface of a storage disk defining a series of radially extensive servo sectors embedded within circumferential zones of data tracks. The sectors are recorded at a constant data transfer rate while each zone has a data transfer rate adapted to disk radius. The drive includes a head and head positioner, a read preamplifier for amplifying analog signals read from, and for amplifying signals to be written to, a storage surface. A circuit board carries drive electronics including a read channel, a servo processing circuit for recovering head location information from the servo sectors, a data block sequencer for sequencing data blocks between a buffer and the storage surface, a buffer memory controller for controlling the buffer, a bus level interface circuit for transferring data blocks between the buffer and a host computer, and a programmed digital controller which functions within a head position servo loop and which also controls the sequencer, buffer controller and bus level interface circuit. As one feature, the servo sectors split data blocks into segments. Segment byte counts in each data block header are used by the sequencer automatically to assemble the segments into data blocks during read and to divide the blocks into segments during write. A single VLSI circuit including the sequencer, servo processing circuit, memory controller and an interface to the microcontroller is disclosed.

High capacity submicro-winchester fixed disk drive

A method for determining the position of a data transducer head within one data track of a rotating data storage disk within a disk drive includes the steps of:

Edge servo for disk drive head positioner

A digital servo system for moving a body, such as the magnetic head of a disk drive, by a distance equal to an integral multiple of a predetermined pitch includes a velocity control unit for causing the body to move at maximum acceleration to a predetermined maximum velocity during a first acceleration mode, to move at the maximum velocity during an optional first coast mode, to decelerate from the maximum velocity to an optional intermediate velocity during a first deceleration mode, to move at the intermediate velocity during an optional second coast mode, and to declerate at the maximum acceleration/deceleration rate to zero velocity during a second deceleration mode. The maximum acceleration/deceleration rate is set equal to a rational multiple of the pitch divided by the square of the sampling time of the digital servo system. Respective first through fifth durations of the acceleration mode, first optional coast mode, first deceleration mode, second optional coast mode, and second deceleration mode are suitably set so that the body travels by a distance equal to an integral multiple of the pitch.

Digital servo system for moving body by a distance equal to an integral

A disk data storage subsystem includes a head and disk assembly. A plurality of sectors in data tracks include a servo portion containing a prerecorded pattern of a plurality of repeating, time staggered, non-phase-coherent bursts, each burst having a predetermined integral fraction radial offset relative to the other bursts. The head is positionable relative to the tracks by a voice coil in response to information derived from a servo portion, a programmed microcontroller supervisor receives operational data storage and retrieval commands from a host system with which the subsystem is operationally associated and controls the position of the head during track seeking and following operations in response to servo information read by the head from each servo portion and further in response to the commands, an interface, with an SCSI interface controller, under the control of the microcontroller supervisor receives the commands and data blocks from the host system and for sending commands, status words and data blocks to the host system, a data sequencer and memory controller under the control of the microcontroller manages flow of data blocks to and from the disk via the head.

High capacity disk file with embedded sector servo and SCSI interface

A high performance, low cost rotating disk data storage subsystem includes a head and disk assembly. A plurality of sectors in data tracks include a servo portion containing a prerecorded pattern of a plurality of repeating, time staggered, non-phase-coherent bursts, each burst having a predetermined integral fraction radial offset relative to the other bursts and having a constant frequency preamble field followed by a unique value field related to its burst spatial location. A head is positionable relative to the tracks in response to information derived from a servo portion, a programmed microcontroller supervisor for receives operational data storage and retrieval commands from a host system with which the subsystem is operationally associated and controls the position of the head during track seeking and following operations in response to servo information read by the head from each servo portion and further in response to the commands, an interface under the control of the microcontroller supervisor receives the commands and data blocks from the host system and for sending commands, status words and data blocks to the host system, a data sequencer and memory controller under the control of the microcontroller manages flow of data blocks to and from the disk via the head and stores the information read by the head means from said unique value fields for subsequent processing by the microcontroller. A servo burst pattern providing phase quadrature and absolute position information, a servo writer, a servo qualification area and a timer, a media defect management method, an amplitude measurement circuit, and a time division control program for the microcontroller are aspects of this invention.

High capacity disk file with embedded sector servo

A driver amplifier circuit for an electromechanical position translator having two coils of substantially equal inductance and resistance is disclosed. The circuit includes an input for a control voltage representing desired translator position and a reference voltage, a very low value reference resistor series connected between the two coils, differentially driven push pull amplifiers connected to drive the coils, and two equal value feedback resistors connected from the reference resistor to inverting inputs of the amplifiers, whereby absolute magnitude of output voltage equals the input voltage plus twice the reference voltage, and wherein zero differential input volts yields zero current flow through the coils.

Amplifier circuit

An improved rotating disk data storage device is achieved in a combination of an optical encoder to detect data track crossings, a servo sector surface on one of a plurality of rotating data storage disks with the surface being filled with a pattern of alternating bursts which are read for relative amplitude and compared to provide track centerline information. A programmed microprocessor and a rotary actuator for the data transducers combine with the other elements to move the transducers from track to track and keep them on track during data read and write operations.

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Los Gatos, CA, United States of America

Ronald R Moon